Pen on Paper

How Does One Write a Serial?

I’m just wondering about the actual mechanics of pen on paper. I obviously know how to write but what I mean is, how does a serial story come about? After writing my last novel, I did a lot of editing (possibly not enough) and linked parts back to other parts, added other bit of information into the beginning so it made sense later on.

But once a serial is published, I can’t really go back and add in parts that I’ve missed or link up ideas that I didn’t have at the start of the story.

I imagine, a writer would have to have a very clear image of the story in their head before publishing. Should the novel be written before publishing even one part or can it be published in serial when the ending hasn’t even been written?